New Redemption Grab Bag now includes an assortment of 500 cards from five (5) different expansion sets. Available at Cactus website.
You are not limited to 3 copies of a card, there is no restriction on the number of copies of a card you can have in a booster deck. You can have up to 7 of the same dominant in a booster deck (since you are still limited by the dominant cap).